Denver’s police chief said Thursday he has ordered extra training and a review of department policies after the second accidental shooting by an officer this month and the fifth in a little over a year.

Police are still investigating the latest shooting Sunday night, but at least two of the accidental shootings have been blamed on gun-mounted tactical flashlights. Such lights have also been cited in other accidental police shootings across the country, including one that killed a man in Texas.

Police Chief Robert White said he is reviewing the use of all such flashlights and will likely require officers who use them to undergo added training. He has already banned officers from using a specific design of such flashlights.

“It’s gotten to the point where I’m concerned about it,” White said Thursday. “We’re mandating additional training.”

The latest incident happened Sunday night near the intersection of South Federal Boulevard and West Alameda Avenue. An officer chasing several car-theft suspects unintentionally fired his gun before taking one adult and three juveniles into custody. No one was hit.

That incident came less than a week after another in which an officer’s gun accidentally went off while he was chasing a man suspected of a probation violation. A bystander was wounded in that incident, though it remains unclear whether she was grazed by the bullet or debris from its impact.

The department had three accidental shootings last year.

White said he is thankful no one has been seriously injured in the shootings. But he said the incidents are particularly troubling because accidental shootings are “more often than not a sign of negligence on the part of the officer.”

While the two shootings this year are still under investigation and the officers involved remain on duty, White said the three officers involved in last year’s unintentional shootings were all disciplined. Punishments ranged from a four-day suspension to a written reprimand.

White said the department is reviewing all of its training and policies to make sure officers are prepared for the situations they face on the street. But it is paying particular attention to special tactical flashlights officers often mount on their weapons.

Two of last year’s unintentional shootings were connected to officers’ use of the flashlights, according to the city’s independent police monitor’s annual report. White responded by banning a specific design of flashlight with an on/off switch located on the gun’s grip just below the trigger guard. He cited three specific brands, but said his ban was not limited to those products.

This page from the City and County of Denver Office of the Independent Monitor 2013 Annual Report shows examples of weapon mounted flashlight systems that are not authorized for use by the Denver Police Department. (Click to enlarge image.) (Denver Police Dept. )

Nationally, at least two men have been shot by officers who fired their handguns when they meant to flip a flashlight switch beneath the trigger.

In Plano, Texas, a narcotics sergeant accidentally pulled the trigger instead of the flashlight switch on his gun as he approached a suspected drug dealer. The shot killed 25-year-old Anthony Alcala. In the Bronx, an officer trying to switch on his pistol’s flashlight accidentally shot an unarmed 76-year-old man, Jose Colon, in the stomach. Colon survived.

Those two shootings, in 2010 and 2011, spurred a lawsuit by Alcala’s family and a debate among firearms-training experts about the wisdom of affixing a flashlight to a gun.

Ken Cooper, a New York firearms and use-of-force instructor, served as an expert consultant to Alcala’s family, who ultimately settled their lawsuit with flashlight maker SureFire LLC. Cooper said SureFire originally developed the flashlight for Navy SEALs but then sold it to police agencies, as well.

“When that happens, the difference between law enforcement and Navy SEALS is thousands of hours of training,” Cooper said.

The benefit of the product, he said, is “you can actually operate the gun and the flashlight in one hand.” But, in stressful situations, the more complicated the setup of the gun, the more danger there is for mistakes, Cooper said.

“Your brain gets cross-wired, and things can happen,” he said.

How much danger is hard to quantify. Cooper said he believes nobody is tracking the number of times that police officers tried to hit a flashlight switch and pulled the trigger instead. Sarah Guy, a spokeswoman for the International Association of Chiefs of Police, said the association doesn’t have statistics or research on flashlight-related gun incidents.

Attachable flashlights also drew fire from Force Science Institute executive director Bill Lewinski, who studies human behavior in stressful and deadly force encounters. In 2011, the institute advised police officers “to avoid a switching device that attaches to a popular gun-mounted flashlight and creates risk of an unintended firearm discharge during high-stress confrontations.”

SureFire did not return requests for an interview. But in a rebuttal to the institute’s newsletter, it said more than 100,000 handgun-mounted lights were in circulation, and only two safety-related incidents had been reported in 24 years.

“These figures alone prove that SureFire WeaponLights, and weapon-mounted lights in general, are safe,” the company said.

While the number of accidental shootings is small compared with the 800,000 calls Denver police respond to every year, White said officers must be held to a high standard when it comes to use of weapons. At a minimum, he said the department will likely require officers who use gun-mounted flashlights to practice special training with them as part of their quarterly firearms training.